feat(material/expansion): allow focus origin to be optional input in focus method (#20912)

Co-authored-by: Jessica Xu <[email protected]>

Author: Jessica Xu

src/material/expansion/expansion-panel-header.ts

@@ -190,8 +190,12 @@ export class MatExpansionPanelHeader implements AfterViewInit, OnDestroy, Focusa
    * @param origin Origin of the action that triggered the focus.
    * @docs-private
    */
-  focus(origin: FocusOrigin = 'program', options?: FocusOptions) {
-    this._focusMonitor.focusVia(this._element, origin, options);
+  focus(origin?: FocusOrigin, options?: FocusOptions) {
+    if (origin) {
+      this._focusMonitor.focusVia(this._element, origin, options);
+    } else {
+      this._element.nativeElement.focus(options);
+    }
   }
 
   ngAfterViewInit() {

src/material/expansion/expansion.spec.ts

@@ -223,6 +223,24 @@ describe('MatExpansionPanel', () => {
     expect(document.activeElement).toBe(header, 'Expected header to be focused.');
   }));
 
+  it('should not change focus origin if origin not specified', fakeAsync(() => {
+    const fixture = TestBed.createComponent(PanelWithContent);
+    fixture.componentInstance.expanded = true;
+    fixture.detectChanges();
+    tick(250);
+
+    const header = fixture.debugElement.query(By.css('mat-expansion-panel-header'))!;
+    const headerInstance = header.componentInstance;
+
+    headerInstance.focus('mouse');
+    headerInstance.focus();
+    fixture.detectChanges();
+    tick(250);
+
+    expect(header.nativeElement.classList).toContain('cdk-focused');
+    expect(header.nativeElement.classList).toContain('cdk-mouse-focused');
+  }));
+
   it('should not override the panel margin if it is not inside an accordion', fakeAsync(() => {
     const fixture = TestBed.createComponent(PanelWithCustomMargin);
     fixture.detectChanges();